package txindex import ( "context" "github.com/tendermint/tendermint/libs/service" "github.com/tendermint/tendermint/types" ) const ( subscriber = "IndexerService" ) // IndexerService connects event bus and transaction indexer together in order // to index transactions coming from event bus. type IndexerService struct { service.BaseService idr TxIndexer eventBus *types.EventBus } // NewIndexerService returns a new service instance. func NewIndexerService(idr TxIndexer, eventBus *types.EventBus) *IndexerService { is := &IndexerService{idr: idr, eventBus: eventBus} is.BaseService = *service.NewBaseService(nil, "IndexerService", is) return is } // OnStart implements service.Service by subscribing for all transactions // and indexing them by events. func (is *IndexerService) OnStart() error { // Use SubscribeUnbuffered here to ensure both subscriptions does not get // cancelled due to not pulling messages fast enough. Cause this might // sometimes happen when there are no other subscribers. blockHeadersSub, err := is.eventBus.SubscribeUnbuffered( context.Background(), subscriber, types.EventQueryNewBlockHeader) if err != nil { return err } txsSub, err := is.eventBus.SubscribeUnbuffered(context.Background(), subscriber, types.EventQueryTx) if err != nil { return err } go func() { for { msg := <-blockHeadersSub.Out() eventDataHeader := msg.Data().(types.EventDataNewBlockHeader) height := eventDataHeader.Header.Height batch := NewBatch(eventDataHeader.NumTxs) for i := int64(0); i < eventDataHeader.NumTxs; i++ { msg2 := <-txsSub.Out() txResult := msg2.Data().(types.EventDataTx).TxResult if err = batch.Add(&txResult); err != nil { is.Logger.Error("Can't add tx to batch", "height", height, "index", txResult.Index, "err", err) } } if err = is.idr.AddBatch(batch); err != nil { is.Logger.Error("Failed to index block", "height", height, "err", err) } else { is.Logger.Info("Indexed block", "height", height) } } }() return nil } // OnStop implements service.Service by unsubscribing from all transactions. func (is *IndexerService) OnStop() { if is.eventBus.IsRunning() { _ = is.eventBus.UnsubscribeAll(context.Background(), subscriber) } }